static void Main(string[] args) { AddressBook book = new AddressBook(); book.UserRemoved += Logger.Instance.Info; book.UserAdded += Logger.Instance.Info; string answer; do { Console.WriteLine("Add user - A, delete user - D, show all users - L, quit - Q"); answer = Console.ReadLine(); switch (answer.ToUpper()) { case "A": { book.AddUser(); break; } case "D": { book.RemoveUser(); break; } case "Q": Console.WriteLine("Exiting.."); break; case "L": { book.AllUsers(); break; } default: Console.WriteLine("Wrong input. Try again"); break; } }while (answer.ToLower() != "q"); }